docs: def generate_vcpu(self, vcpu_num):
          """
          Generate <vcpu> domain XML child
  
          Args:
              vcpu_num(str): number of virtual cpus
  
          Returns:
              lxml.etree.Element: vcpu XML element
          """
  
          vcpu = ET.Element('vcpu')
          vcpu.text = str(vcpu_num)
          return vcpu